The bearings of rotary drilling bits are of critical importance to the useful life of the bit. The bearings must have an extended life under conditions of lubricant over-heating, extreme shock loading, lubricant contamination, and abrasion. Lubricant overheating with charring and outgasing of the lubricant and the consequent bearing deterioration is a common problem.
The present invention eases the bearing problems by effectively reducing the velocity between sliding bearing members by selectively distributing the sliding contact of mating faces of such bearing members over a significantly greater area which is utilized as a particular portion of such area increases in temperature.
Specifically pertinent prior art to the present invention is not known. However, typical prior art is noted and referenced as follows:
U.S. Pat. No. 3,680,873 to Garner discloses an improved seal to prevent contamination of the bearing lubricant; PA1 U.S. Pat. No. 3,995,917 to Quinlan discloses an improved bearing and bearing material comprising an aluminum bronze alloy with a particular heat treatment; PA1 U.S. Pat. No. 4,067,406 to Garner includes the disclosure of providing increased journal bearing area to increase the life of extended insert cutters.